Cannot use Picture-in-Picture while in YouTube TV while using Google Chrome on my laptop running Fedora 30.
REF: https://www.reddit.com/r/youtubetv/comments/dgtkwt/how_to_force_enable_chromes_pictureinpicture/
Found this on Reddit recently. I have this working in Firefox 69.0.3 on Fedora 30. It works nice. You can move the window and resize.
How To Force Enable Chrome's Picture-in-Picture Feature Policy for YouTube TV [Linux/Mac/Windows]
1. Download AND install: Feature Policy Tester DevTools Extension (https://chrome.google.com/webstore/detail/feature-policy-tester-dev/pchamnkhkeokbpahnocjaeednpbpacop)
2. Download And install: Picture-in-Picture Extension (https://chrome.google.com/webstore/detail/picture-in-picture-extens/hkgfoiooedgoejojocmhlaklaeopbecg?hl=en)
3. Complete the following steps on each visit until somebody creates an extension that persists choices
4. Visit tv.youtube.com
5. Open DevTools (right click -> inspect, ctrl+shift+j, etc)
6. Select Feature Policy tab
7.Check persist checkbox on the left side
8. Check picture-in-picture policy on the right side
9. Close DevTools and start PiP by clicking the PiP extension icon or press alt+p to start
Firefox is even better...
1. Navigate to about:config
2. Set media.videocontrols.picture-in-picture.enabled to true
3. Set media.videocontrols.picture-in-picture.video-toggle.enabled to true
4. A working PiP icon now appears in the center of the right border of playing YTTV videos, no need to jump through hoops on each request.
Although, depending on how they handle the Feature-Policy headers going forward, you might need to play with the featurePolicy flags in the future (risky, because some of the flags are great).